The quality of wireless links is deteriorated by factors that drop the performance of a time-variable channel, such as interference, flat-fading, and frequency selective fading. In order to dynamically adapt such channel variation, the IEEE 802.15.3 standard for HR-WPAN supports five different data transfer speeds. Therefore, a communication system may effectively perform data communication by properly selecting one of the data transfer speeds or deciding a MAC frame size according to a channel state.
Wireless mesh networks (WMN) were introduced as a critical technology for next generation wireless networking. Since the WMNs are dynamically self-systemized and self-configured, each of nodes automatically establishes an ad-hoc network and sustains mesh connection. The IEEE 802.15.5 task group has been studied a framework for wireless mesh topologies which are schedulable, stable and sharable with PAN devices.
In order to implement an effective communication system, a wireless device has to select the optimal piconet coordinator (PNC) according to a channel state. However, there were not many studies progressed for developing a method for selecting a PNC for improving throughput in a wireless mesh network.
High speed mesh architectures were introduced for providing path diversity between a mesh router and mesh clients in wireless mesh network. For example, a method of selecting a routing path was introduced in U.S. Pat. No. 7,058,021 entitled “Selection of routing paths based upon routing packet success ratios of wireless routes within a wireless mesh network”. In U.S. Pat. No. 7,058,021, a selection method was provided to select a routing path based on a routing packet success rate of wireless roots in a wireless mesh network, and the selection method includes a method for deciding an optimal root based on a path quality of roots for access nodes of the wireless mesh network. In more detail, a wireless root having the highest success rate is initially selected, and other wireless roots having success rates in a predetermine range of good success rates are selected. Also, path availability, consistency, and throughput are considered to search the optimal path in the WLAN environment.
Adaptive robust tree (ART) for LR-WPAN was described in IEEE 802.15.5 TG. The ART is based on meshed tree approach and focuses on meshed tree routing, multicasting, and key pre-distribution. Related to this, a method of selective packet delay (SPD) was introduced to improve the performance of high speed downlink sharing channel (HS-DSCH). The SPD method employed an N-channel stop and wait retransmission (SAW) scheme of high speed downlink packet access (HSDPA). The introduced SPD controls packet transmission according to a channel state. If the channel state is bad, the packet transmission is delayed and an assigned time slot is given to other users having the good channel state. Therefore, the average transmission delay can be reduced in burst error environment.